In existing proposals for a fixed radio access system, each subscriber premises is provided with a residential service system which includes a residential transceiver unit and a residential base unit. The residential transceiver unit establishes and controls one or more radio communication channels with the remote base station, with a typical transceiver unit being capable of providing three 32 kbit/s channels. The radio transceiver unit also handles the air side allocation of resources. The residential base unit may be a subscriber line interface card and typically includes a multiplexer and network termination equipment to provide the subscriber with typically up to two PSTN lines and an S/T interface for ISDN. It is emphasised that the residential base unit and the residential transceiver unit may be arranged together as an integral unit, or the components of the unit may be distributed. Accordingly the residential baseband unit and network termination equipment may be either collocated, or separate, connected by a suitable communications channel employing for example ITU-TREC 1-430 (S-Bus) technology.
Although this system works well, providing reliable and relatively economic installation and operation, the system lacks flexibility in some aspects and this can affect ease of installation and operation of the network, with a consequent effect on capital and recurring costs. The available bandwidth that can be delivered to a given subscriber is limited to that available through one residential transceiver unit. The bandwidth of 96 kbit/s (3.times.32 kbit/s channels) available from a typical residential transceiver unit would be sufficient to provide a subscriber with up to three voice calls at 32 kbit/s ADPCM but is not enough to provide a subscriber with 2B+D ISDN basic rate which requires a bandwidth of 144 kbit/s. It has been proposed to provide a subscriber with a further residential subscriber system but this increases installation and equipment costs. Similar considerations apply to broadband broadcast services. Further, increasing residential subscriber system capacity on a per subscriber basis results in poor utilisation of available bandwidth and provides very limited or no concentration of series between the subscriber installation and the residential transceiver units. In addition there is no redundancy in the event of residential subscriber system failure, power loss or radio link.